High prevalence of smoking in patients with adrenal incidentalomas: causality or case selection?

Autonomous cortisol secretion and possible autonomous cortisol secretion (ACS/pACS) are associated to an increase of cardiovascular risk factors such as hypertension, diabetes mellitus and dyslipidaemia. To our knowledge, the prevalence of smoking, another well-established risk factor for cardiovascular disease, has not been studied in detail in people with ACS/pACS or adrenal incidentalomas.

Patients with adrenal incidentalomas were examined with the 1-mg overnight dexamethasone suppression test (cortisolONDST). Information about current smoking was collected from the patient's records.

We studied 1044 patients, of whom 370 (35%) were current smokers. Of these, 22% had bilateral AI compared to 12% of the non-smokers (P < 0.001). Among patients with unilateral adrenal incidentalomas, smokers had larger adrenal incidentalomas than non-smokers (22 mm vs 19 mm, P < 0.001). Smokers also more often had cortisolONDST ≥50 nmol/L than non-smokers, 54% vs 40% (P < 0.001), a finding independent of the size of the adrenal incidentaloma in patients with unilateral adrenal incidentalomas.

In the present study of patients with adrenal incidentalomas, the prevalence of current smoking was higher than in the general population. Furthermore, smokers had larger unilateral adrenal incidentalomas, more often bilateral adrenal incidentalomas, and more frequently ACS/pACS. Whether smoking is a risk factor for adrenal incidentalomas and ACS/pACS or our findings are due to case selection needs to be further studied.